IPTV (and Digital Cable TV) Performance Management Alan Clark Telchemy Incorporated IIT VoIP Conference 2008
Outline IPTV/ Digital Cable service architectures What do service providers need to know? The myriad aspects of IPTV performance IPTV performance monitoring architecture
IPTV/ Digital Cable service Scrambled video streams Mix of scrambled/ unscrambled streams Customer Premise Video sources DRM 3 rd party Digital video content Unscrambled video streams IP Set Top
Video Frame Structure I B B P B Typical assumptions: - GoP length of 15 or 30 (have seen 250, can be variable) - I frame bandwidth ~ 40% of total bandwidth - P/B frame bandwidth ~ 3-5% of total bandwidth per frame Impact of high motion? - VBR - leads to bandwidth spikes - CBR - can lead to motion related blockiness
Video Frame Structure and Packet Loss I B B P B Error in I frame will propagate through following P and B frames Error in B frame will only impact this frame Error in P frame will propagate through following P and B frames
The myriad aspects of IPTV performance Transmission performance Equipment faults, limited bandwidth, unexpected traffic patterns, subscriber access or LAN problems Configuration or equipment errors Mismatch between encoder settings and decoder capabilities Equipment fault or unwanted behavior Non-optimal encoder configuration GoP too long or short Bandwidth consumption too high or variable Unexpected content Video loss - blank, frozen, noisy video Loss of video feed Excessive error rates on video feed Software bug in video encoder
What do service providers need to know? Head-end perspective Are all streams conforming to specification? Do streams have active content? How is bandwidth being used? Impact of bandwidth limitation * content on quality? Subscriber perspective Network problems (loss, bandwidth ) affecting individual/multiple subscribers? Impact of codec configuration * transmission problems on quality? Overall user view of service provider? Overall user view of individual channels?
IPTV performance monitoring Management Middleware Embedded agent in STB Video sources IPTV probe DRM 3 rd party Digital video content Embedded probe in router
IP Set Top/ Agent Architecture EPG & Menu Graphics HDMI DRM Descrambler Video/Audio Decoder Playout Buffer Comp S- Video UDP/RTP/MP2TS UDP/MP2TS UDP/RTP MP2TS SQlive Network Interface Set Top Box
IP Set Top Agent Architecture Content Analysis Level of motion/detail Content related alerts RTP, MPEG Decode & Frame Identification Playout Buffer Emulator Compute Compute Compute Per Per Frame Frame Per Quality Quality Frame Quality Perceptual Model Metrics Aggregation & Reporting User Experience FEC, R-UDP Model Error Propagation through GoP Time view Channel view SQlive agent architecture Stream being watched by subscriber
Head-end Probe Architecture Content Analysis Level of motion/detail Content related alerts RTP, MPEG Decode & Frame Identification Playout Buffer Emulator Compute Compute Compute Per Per Frame Frame Per Quality Quality Frame Quality Perceptual Model Metrics Aggregation & Reporting FEC, R-UDP Model Error Propagation through GoP Time view Channel view SQlive agent architecture All video streams
Perceptual Quality Model Perceptual Quality Model Per-Frame Quality Estimates Q f(i), Q f(i+1) Video Integration Model I/B/P frame Bandwidth Content data Bandwidth Limitation Model Content Sensitivity Models Perceptual Quality Estimate MOS-V MOS-A Audio quality Estimates A f(i), A f(i+1) Audio Integration Model
Performance verification Main focus on subjective testing Expert panels of 16-20 viewers SD (480i) and HD (720p, 1080i and 1080p) tests Mix of DCR and ACR tests
Scrambled vs Unscrambled Video Unscrambled MOS-V = 3.1 EPSNR = 27.5 I frame packets Received 6225 Lost 42 P/B frame packets Received 20779 Lost 40 IP Statistics Loss rate = 0.23% Scrambled MOS-V = 3.0 EPSNR = 27.0 I frame packets Received 6367 Lost 42 P/B frame packets Received 20637 Lost 21 IP Statistics Loss rate = 0.23%
Summary IPTV/ Digital Cable service architectures What do service providers need to know? The myriad aspects of IPTV performance IPTV performance monitoring architecture